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发帖数: 233 | 1 据英国《每日邮报》1月7日报道，英国科学家找到了“急性癌症”的形成原因：细胞内
的染色体发
生“爆炸”破坏了DNA，从而让人有可能在短时间内患上癌症。相关论文发表于《细胞
》。
传统理论认为癌症是人体经历成千上万次的细胞突变后，慢慢演化的结果。但英国著名
的疾病研究机
构桑格研究所的新发现推翻了这种看法。这暗示了不管人们怎么努力保持身体健康，也
不能保证命运
不会拿他们开玩笑。同时还说明了为什么有些人在体检时根本没发现癌症痕迹，但数月
后突然就被诊
断患上这种疾病了。
桑格学院的科学家是通过研究750个肿瘤的遗传缺陷后得出以上结论的。其中大部分的
案例都与传统
理论相符，染色体的损坏是常年累积的结果。然而，其中至少有1/40的肿瘤不符合“标
准模式”，有的
染色体似乎是在一夜之间遭到破坏的。
参与此项研究的坎贝尔博士称：“测验结果太让我们惊讶了。在一个细胞里面，染色体
经过一次或者是
多次爆炸成为碎片。如果这个细胞开始笨拙地修补，把碎片杂乱的缝合起来，这样就破
坏了原来的
DNA结构，为癌症的快速形成提供了条件。”
坎贝尔博士表示：“这个细胞应该说‘好吧，我放弃’，而不是像对待昂贵的瓷器一样
，把染色体拼接
回去。细胞试图修复一个不可修复的东西，最后造出一个灾难性的、能让癌症更快形成
的基因组。”
这种“急性癌症”在骨癌里面特别常见，大概1/4的患者身上都能看到明显的染色体受
损特征模式。科
学家目前还不能肯定是什么引起了这种染色体“爆炸”，但有嫌疑的罪魁祸首包括X光
和晒伤。坎贝尔
博士称：“如果我们能了解根本的病因，或许就可以防止患上这种癌症。”
更多阅读
英国《每日邮报》相关报道（英文）
http://www.dailymail.co.uk/health/article-1344740/Why-cancers-d
instant--cells-explode-wreaking-havoc-DNA.html
Why some cancers seems to develop in an instant - cells can explode
wreaking havoc in DNA
By FIONA MACRAE
7th January 2011
The mystery of 'instant cancers' - tumours that seem to appear out of
nowhere - has been solved by British scientists.
In some cases, a single apocalyptic ‘explosion’ in a cell can cause as
much damage to the DNA as decades of hard living.
A model of a DNA Molecule. Scientists have found one in 40 cancers could
develop rapidly after an unexpected cell explosion causes DNA damage
The finding, from the Wellcome Trust Sanger Institute near Cambridge,
contradicts the long-held theory that cancer is the consequence of
hundreds, or thousands, of mutations that build up over a person’s
lifetime.
It suggests that no matter how healthy some people try to be, fates is
conspiring against them. And it helps explain why some people are
diagnosed with cancer only months after x-rays or other tests found no
trace of the disease.
The discovery was made from the study of the genetic flaws in 750
tumours.
In most cases, the damage seen to the chromosomes fitted with the
conventional picture of cancer creeping up over many years.
But at least one tumour in 40 didn’t fit the standard pattern, the
journal Cell reports.
Instead, the damage appeared to have been done almost overnight.
Researcher Dr Peter Campbell said: ‘The results astounded us. It seems
that in a single cell, in a single event, one or more of the
chromosomes explode - literally into hundreds of fragments.’
If the cell then botches the repair, stitching the fragments back
together in a ‘higgledy piggledy’ fashion, the damage to its genome, or
cache of DNA, leaves it ripe for the rapid development of cancer.
Dr Campbell said: ‘The cell should say “that’s it”, and give up, but
instead it tried to piece the chromosomes back together like a valuable
piece of porcelain.
‘They attempt to reconstruct the unreconstructable and they wind up with
a disastrous genome that shortens the road to cancer.’
The phenomenon is particularly common in bone cancers, where the
distinct pattern of damage is seen in up to one in four cases. But it
thought to be to blame for more than one in 40 of all cases of the
disease.
Dr Campbell said: ‘Many cancers will take years, decades, to develop.
But we also know that in some patients cancers seem to appear much more
quickly than that.
'We have examples of people who had a totally normal mammogram or other
x-ray and within a few months they develop a nasty aggressive cancer
and it may be that a single catastrophic event shortened the
development.’
The researchers aren’t sure what triggers such the catastrophic damage
behind ‘instant cancers’ but possible culprits include x-rays and
sunburn.
Dr Campbell said: ‘If we can understand its roots, we may learn how to
prevent that kind of cancer happening.’
The study is part of a landmark project to chart the genetic flaws in
dozens of types of cancer.
In future, every patient could have their own 'mutation chart', mapping
the precise flaws behind their illness and indicating the best drugs to
treat them. |
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